Testing apparatus for surface finish



,Nov. 12, 1935. R. E. w. HARRlSON 2,020,548

TESTING APPARATUS FOR SURFACE FINISH Filed Oct. 21, 1930 gnuentoz .10 I Foam/41 #4 2250 2mm i .I e

' PA EN "2,020,548 msirmo'srrm'ms For: summon V Robert E. Cincinnati, Ohio; asslgnor to Cincinnati Grinders Incorporated, (Jincin nati, hio, a corporation of Ohio H a application o t 21, 19st, ser n'nmssazas I som (cue-s1).

'This invention relates toimprovements in ap- 1 3, but indicating a'poor, ununiform finish. paratus fortesting and comparing machine finf Figure 5-is a diagrammatic view; of a mod1'- v L .ished surfaces. flcation embbdyingthe invention; 'In the past, the quality of finish or surface Figure 6 isjaside elevation of the generator Y produced on work pieces was. determined 01' classhead and its supporting arm, the main casing ified by either the operator of the machine pro 10' being shown insection; V V, Y dncin'g the-finish or surface, the. man in charge," As was noted above, thefmachine finish on g or the inspector passing onthe work and its work pieces and especiallythe grinding finislu finish at its'alleged" completion. In otherfwords, was heretofore classified by sight of- 'various- 19 the quality of the or surface was deter individuals-whose opinions of the quality'of the -min d'by ey by Y us parti s hav n more varied greatly. depending onexperience,

'or less eatended experience in: such matters. It use, and other circumstances. By' the use of this is a well known-fact thatwhatwould be-a godd. invention the unreliable opinions of' the various 1 finish to oneman or' examiner'would be an ex- "individuals may be discarded 'andrthe finish on cellent or poor finish to another depending so i the work minutely and. positively. measured; and

" chined articles.

13* on the type or quality of work accusto determined and the .fini'sh .on' successive "work. to be received r produced; By a. device of this pieces'accurately compared. .invention the finality or type ,of finish can be Referringnow to thedrawing illustrating'one 4 readily determinedor ascertained, as well as possible embodiment of the invention in which.

compared with a formerly established deter similar reference. characters are employed to g minator. j c' denote the semen! similar parts.- Therefer- It is," therefore, orient the principal objects ence character 10 indicates, a housing containof the present invention to provide a-mechanism. mgthe measuring =andzdeterminingmechanism. for determining the quality of surface or iin The housing In may 'besupported on an exten- .ish on a machined article. v sion of a table or-bench II which comprises 25 Another object oftheinvention is the .provi-, legs l2 supporting a shelf 13. Brackets l4 and ,sion of'a mechanism'for visiblyand audibly in- 15 are carried bythe shelf [3 and have jour dicating thequalitywof surface finish of manaledin them shafts-wand II, the former supporting the idler sprocket l8 while the latter Another object of the invention is the pro-- hasseeuredthereto the sprocket l9. .A 1

' ,vision of aself-c'ontained testing-mechanism for' pui1ey 20 secured on the shaft l1 con: u presenting successive work pieces to a surface. *nected bytransmission belt or the like j2l with -indicator for proper determination thereof. a pulley 22 ongtheshait of a motor or prime Other" objects and advantages ofthe, present mover 23 supported by the shaft IS in operative Tinvention should bereadily apparent by refer-' relation; to the-supporter pedestal l5. A car-. 5'

ence to the following specification considered in 1 rier or belt Zl is trained about the sprock- 'xconju'nction with the accompanying ets Iii-and IQ; forcarrying work pieces alon illustrating one possible 'form of the invention the upper surface 25 of'the table for pr'esenta- 1 and it is to' be understood'that modifiation to 'the'testing'mechanism in the housing 40. .tio ns maybe made intlie exact structural-de- III. The 'oppositesides of the transmission belt f tails there shown and descflbei'wlthin the'scope- I 24 are connected by pinsfor the like 26 which I. i

of the-appended claims, without departing from serve as'abutments for the" work 21 -and urge or exceeding'lhespirit of the invention; s a said work along thesurface 25.. One side of- In t e drawing: the belt 2l.is,provided with a series-of cams 28 'i Figure 1 is a 'front elevational view ofiatestadjacent to which the opposite ends. of successive 45 ing or inspection mechanism thelimwork pieces arepositioned while being trans-.

; 1 --pmve nt s this in 7 ig ported past the testing apparatus for apurpose.

' Figure'2 isad 'ammatic view-illustrating laterto-appear. f.

indicating c n -ts Q D yd-inthls .Jngeflerah'the testing and inspection appa {so invention. ratusfor determiningthe suriacefinishon workso' V "work piecejmany times enlargedg-zillnstrating Figure 3 is'a fragmentary offa pieces a means for setting p b l tions or impulsesrepresentativef of the finish -a relatively-good, e being tested or inspected,-'which pulsations -or- Figure .4 is airafgmentaryofimpulses arefthenmeasuredto determineltheir a'-work piece, many enlarged, -slmila r'to' characteristicsfwhich indicate of v I meter,

finish being" tested. More specifically, the invention comprises generating impulses representative of the surface being tested or inspected amplifying said impulses to a point for operating an air vibrator or loud speaker, or when the impulses are electrical for operating a current fiow or an electrical current oscillations recorder, such as an oscillograph.

The testing and measuring apparatus shown in the drawing comprises a pulsations generator 29 of the electro-magnetic type for engagement with the work for setting up an alternating current or electrical energy pulsations which are fed to any desirable current amplifying mechanism, such as the usual in-putradio amplifying element or tube,

30. The electrical energy is transmitted from the in-put amplifying element 30 through the additional amplifying elements or units 3|, 32 and 33 terminating in a transformer 34. The secondary circuit 35 extending from the transformer 34 terminates in a double throw switch 36. This switch is utilized for connecting the secondary circuit 35 with an air vibrator or loud speaker 3'! whereby the electrical frequency may be heard or for connecting the said secondary circuit with a visible indicator, such as a millivoltmeter 38.

In order, however, that the needle or indicating element of the meter 38 may be actuated it may to one another and of uniform spacing with the grooves between them comparatively shallow,

- while in Figure 4 the ridges are unequally spaced having grooves therebetween, in some instances, of considerable depth. By passing a work piece at a uniform speed, as shown in Figure 3, beneath the generator a series. of uniform pulsations are generated which will result in a high pitched tone emanating from the loud speaker 31. and will result in a slight deflection of the needle or indicating point of the meter 38. On the other hand the surface of the article, shown in Figure 4, will cause to be generated a current oflower frequency than the frequency produced by Figure 3, which will result in a low, rasping, guttural sound to be received from the speaker and a relatively wide deflection of the needle of the meter. this it 'will be seen that finishes of different grades may be readily tested and classified.

The generator 29 may be of any well known electro-magnetic type but as shown in Figure 2 may comprise a field or coil 40 having extending therethrough a magnetic conducting core 4|. Coupled to one end of the core 4| is an arm 42 pivoted at 43 and having a chiseled sapphire 101 other vibrator 44 at its other end. The sapphire 44 is passed over the surface of the work 21 thereby oscillating the arm 42 about its-pivot 43 and axially shifting the core 4|. The shifting of the core 4| cuts the lines of magnetism of the generator 29 causing electrical pulsations or current to pass along wires 45 having a frequency depending on the number and shape of the ridges and grooves in the surface of the work. The current is fed by the wires 45 to the in-put amplifying The closer the ridges to onev another From the secondary circuit 41 of the amplifying stage 5 32. This is repeated throughout the amplifying stations. Each of the amplifying elements is provided with a filament or electron emitting member 43 which supplies a medium for transferring the current from the primary or in-put 10 circuit of each amplifying unit to the next. Each of the filaments or electron emitting members 48 is connected by a suitable lead to the power pack and rectifier 49 which is coupled through the usual transformer 50 to the main power lines 5| 5 and 52.

It is to be understood that the parts 4|I43 shown in Figure 2 comprise the functioning elements of the generator which are as an entirety 1 and 6. The stylus 44 has a lateral swinging movement about the horizontal pivot 43, thus vibrating in accordance with irregularities of the work piece being traversed therebeneath.- The generator unit as a whole is carried by the arm 25 62A which is in turn pivoted to a bracket member or lug projecting forwardly from the casing HI, thus having the capacity for vertical swinging movement in response either to pronounced variations in the position of the stylus, or to the 30 lifting action of the cam members 28.

In order to measure or inspect successive work pieces and to pass the vibrator from one work piece to the next, the cam members 28 are adapted to ride under the arm 42A and raise it out of 35 engagement with the work before the said vibrator can snap off of the end of one work piece and snap back on to the next work piece thereby preventing a very disagreeable noise emanating from the loud speaker and eliminating the wide 40 deflection of the meter at the end and beginning of testing of each work piece. .As shown in Figure 1, the work pieces to be inspected or measured are placed at the right hand side of the table II with the operator facing the housing or'45 cabinet l0 and positioning successive work pieces on the belt or carrier 24 and placing the finished or inspected work pieces in suitable receptacles or containers placed at the left hand side of the table II. The arm 42A and generator 23 are held 50 againstthe work and actuated about the pivot of the arm toward the work by gravity.

In practice and when using the air vibrator or loud speaker. 31 as a testing medium a plurality of previously finished pieces conforming o the 55 various standards of finish may be providedand passed beneath the generator to acquaint the operator with the sound or tone to be expected from the speaker as the work pieces to be tested are subjected to the action of the machine. Simi- 60 larly, the deflection of the needle of the meter may be noted as the standard to which subsequent work pieces must measure up.

The modification, shown in Figure 5, illustrates the use of an oscillograph 53 in place of the milli- 65 voltmeter 38. The oscillograph will photographically record the extent of the oscillations in the electrical current set-up by the work and genera tor. The finer the finish the more uniform the photographic impressions of the oscillations while 70 the poorer the finish the more ununiform or ragged the impressions.

From the foregoing description it will be seen that a device for positively determining the finish on a work piece has been provided which finish 75 may be measured by hearing with the loud speaker, by sight with the current flow meter, or by a gra'phic record with the oscillograph.

What is claimed is: 1. In a device for testing the surface finish of a work piece, the combination of a support, a finish testing mechanism. associated-with the support including a housing, a current generator for generating a current representative of the finish being tested and including an arm, and a vibrator carried by the arm, the vibrator being adapted to engage the surface to be tested, the arm being pivotally secured to the housing for movement away from the surface being tested, means for advancing thework relative to the vibrator to actuate said vibrator and generate a current representative of the finish being tested, means for actuating the arm and generator about the piv otal mounting of the arm to prevent the vibrator from snapping oi the end of the surface being tested and means carried by the housing for determining the characteristics of the generated current.

'2. In a'device for testing and determining the finish on machined articles the combination of a table, an endless conveyor on the table for actuating work pieces relative thereto, a vibrator which is determined by the rate of vibration of the vibrator, meansfor amplifying the generated current, means for accurately determining the characteristics of the generated current for thereby accurately determining the finish on the work, and means associated with the endless con-.

veyor for actuating the vibrator about its pivot for raising same from the surface of the work being tested prior to the snapping off of the vibrator from the end of the work.

3. In a mechanism for testing the surface finish on a plurality of work pieces which are actuated in a continuous stream relative to the surface tester the combination of a conveyor for shifting said work pieces, an arm mounted for pivotal movement in a back and forth direction as re-- spects the surface being tested and for additional movement in a direction toward and from said surface, a stylus associated with the arm and contacting with the surface of the work being tested as it is being shifted by the conveyor and whereby the arm is oscillated in one plane about its pivot, a generator associated with the arm for generating a-current representative of the oscillations of the armas imparted thereto through .face tester the'combination of a conveyor for measuring the current, and additionalmeans for oscillating the arm in a plane transverse to that in which it is moved through the stylus for rais 5 ing said stylus from the surface of, the work near opposite ends thereof.

4. In a mechanism for testing the surface finish on a plurality. of work pieces which are actuated in a continuous stream relative to the surm shifting said work pieces, an arm mounted for pivotal movement in a back and forth direction as respects the surface being tested and for additional movement in a direction toward and from 15 said surface, a stylus associated with the arm and contacting with the surface of the work being tested as it is being shifted by the conveyor and whereby the arm is oscillated in one plane about its pivot, a. generator associated with the arm for 2 generating a current representative of the oscillations of the arm as imparted thereto through the stylus, means for amplifying the generated current to a' measurable amplitude, means for measuring the current, additional means for oscillating the arm in a plane transverse to that in which it is moved through the stylus forrais ing said stylus from the surface of the work near opposite ends thereof, and means for' further amplifying the current prior to its flow to the sight or graphic determinators.

5. A machine for' testing the accuracy of the surface finish of a multiplicity of work pieces ineluding a support, means for serially translating a multiple number of work pieces consecutively past the support,'a direct contact stylus mounted on the support for movement relative thereto and extending-in a position to engage and traverse the surface of the work pieces during their translation, a current generator operated by the stylus 40 for generating a current proportional to the variance of the surface of the work piece being tested from a geometrical plane, means for amplifyingthe generated current, and an instrumentality coupled in the circuit of said amplified current and. operable by a generated current of intensity indicative of unsatisfactory finish on the work piece.

6. A mechanism as specified in claim 5 in which automatically operated cam means are provided for intermittently raising and lowering the stylus mechanism to prevent undesirable engagement thereof with the terminal portions of the successive translated work pieces.

ROBERT E. W. HARRISON. 

